Introduction to Amazon VPC

Provision a logically isolated virtual network with full control over IP ranges, subnets, and routing.

Amazon VPC lets you launch AWS resources into a virtual network you define.

A /16 CIDR block gives 65,536 addresses; AWS reserves the first four and the last IP in every subnet.
Public subnets route to an Internet Gateway; private subnets reach the internet via a NAT Gateway.
You cannot resize a VPC CIDR after creation without adding secondary blocks, so size generously.